Adds code to generate compile_commands.json, run 'scons cdb' to generate it

.gitignore

@@ -1,6 +1,8 @@
 # Objects.
 .scons-cache/
 *.os
+*.obj
+
 
 # SConstruct
 .sconf_temp
@@ -12,3 +14,7 @@
 
 # Editors
 .vscode/
+
+# Clangd
+.cache/
+compile_commands.json

SConstruct

@@ -5,6 +5,10 @@ from pathlib import Path
 # TODO: Do not copy environment after godot-cpp/test is updated <https://github.com/godotengine/godot-cpp/blob/master/test/SConstruct>.
 env = SConscript("godot-cpp/SConstruct")
 
+env.Tool('compilation_db')
+cdb = env.CompilationDatabase('compile_commands.json')
+Alias('cdb', cdb)
+
 # Add source files.
 env.Append(CPPPATH=["src/"])
 sources = Glob("src/*.cpp")